1. Field of the Invention
The present invention relates to updating distributed databases, and more particularly to a method and system for detecting fraudulent data update.
2. Description of the Related Art
Operating systems (OS) of computers are provided with a security function such as access control and file protection in order to prevent fraudulent update of files and databases. For example, as a user logs in a computer, the operating system checks the password and a database access privilege to thereby limit database update to specific persons. Since the operation system stores data update log, it is possible to check fraudulent data update by unprivileged persons. Computer security technology is described, for example, in "Information Security", Nikkei McGraw-Hill Corp., 1987, pp. 243-249.
Conventional security technology is effective for the prevention of fraudulent data update by unprivileged persons, however, it cannot deal with fraud by insiders having data update privilege. It is not easy to detect fraudulent data update by insiders of databases, particularly databases distributed at factories, sales offices, business offices and the like of companies and monetary institutes.